Significance and Use

A soil sampling and analysis program provides a direct means of determining the concentration and distribution of radionuclides in soil. The presence and extent of neptunium-237 is of particular interest because it is one of the more mobile transuranics in terms of migration and plant uptake. Since soil is an integrator and a reservoir on long-lived radionuclides, and serves as an intermediary in several pathways of potential importance to humans, knowledge of the concentration of neptunium-237 in soil is essential.

1. Scope

1.1 This guide covers the determination of neptunium-237 in soil by means of radiochemical separations and alpha spectrometry. This guide provides options in the selection of sample preparation, separation, and measurement. Although neptunium-237 is not a component of global fallout, it is a product of production reactors and spent fuel processing. This guide is designed for analysis of ten grams of soil previously collected and treated in accordance with Practices C998 and C999 . Larger-size samples of environmental soil may also be analyzed, as long as the concentrations of interferences such as uranium and thorium are at or near environmental concentrations. Depending on the choice of a sample dissolution method, all chemical forms of neptunium may not be completely solubilized. This guide should allow the determination of neptunium-237 concentrations from sub becquerel per gram levels to applicable standards depending on count time, sample size, detector efficiency, background, and tracer yield.

1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

C859 Terminology Relating to Nuclear Materials

C998 Practice for Sampling Surface Soil for Radionuclides

C999 Practice for Soil Sample Preparation for the Determination of Radionuclides

C1000 Test Method for Radiochemical Determination of Uranium Isotopes in Soil by Alpha Spectrometry

C1001 Test Method for Radiochemical Determination of Plutonium in Soil by Alpha Spectroscopy

C1163 Practice for Mounting Actinides for Alpha Spectrometry Using Neodymium Fluoride

C1284 Practice for Electrodeposition of the Actinides for Alpha Spectrometry

C1317 Practice for Dissolution of Silicate or Acid-Resistant Matrix Samples

C1342 Practice for Flux Fusion Sample Dissolution

C1387 Guide for the Determination of Technetium-99 in Soil

C1412 Practice for Microwave Oven Dissolution of Glass Containing Radioactive and Mixed Wastes

D1193 Specification for Reagent Water

D1890 Test Method for Beta Particle Radioactivity of Water

D3084 Practice for Alpha-Particle Spectrometry of Water

D4962 Practice for NaI(Tl) Gamma-Ray Spectrometry of Water

Keywords

alpha spectroscopy; americium-243; beta counting; extraction chromatography; gamma-ray spectroscopy; neptunium-239; neptunium-237 determination; soil analysis; Soil (radioactive analysis); Neptunium-237;

ICS Code

ICS Number Code 13.080.10 (Chemical characteristics of soil)

DOI: 10.1520/C1475-05R10E01

ASTM International is a member of CrossRef.

ASTM C1475